1. Field of the Invention
The present invention relates to a head-protecting airbag apparatus provided with an airbag, which, when fed with inflation gas, is deployable downward from upper edge of side windows of a vehicle to protect occupants' head.
2. Description of Related Art
Conventionally, a head-protecting airbag apparatus is provided with an airbag folded and housed in the upper periphery of windows inclusive of upper part of pillar portions. The housed airbag is covered by an airbag cover, and when fed with inflation gas, inflates to push and open the airbag cover, and deploys downward from the upper periphery of windows. The inflated airbag covers the vehicle's interior side of pillars and windows.
In the prior art, Japanese Patent Laid-Open No. 11-091490 is illustrative of a head-protecting airbag apparatus provided with a jump stand that prevents a deploying airbag from entering the vehicle's outer side of pillar garnish covering the inner side of a pillar portion, such that the airbag smoothly deploys toward inward of vehicle. This jump stand is disposed above, and in vehicle's outer side of, a pillar garnish, and includes a slanted guide face, in the top surface thereof. The jump stand serves to guide an inflating airbag inward of vehicle over the upper end of the pillar garnish, by having the airbag slide on its guide face.
Japanese Patent Laid-Open No. 2002-067860 is illustrative of a head-protecting airbag apparatus provided with a guide bracket. The guide bracket has a U-shaped cross section. The guide bracket includes two guide walls confronting each other, and a joint wall joining the two guide walls at the outer ends of the guide walls, and serves to guide the inflating airbag to predetermined direction inside the vehicle.
This guide bracket accommodates the folded airbag between the two guide walls, and upon airbag deployment, allows the airbag to protrude from an opening provided between the leading ends of the guide walls while controlling the deployment direction of the airbag by the two guide walls. In other words, since the bracket guides the airbag with two guide walls extending from the joint wall, the guide bracket secures more stable airbag protrusion in a predetermined direction in comparison with the jump stand. As a result, upon airbag deployment, the guide bracket prevents the airbag from bumping against or hitching on the pillar garnish, and prevents the airbag from bumping against an airbag cover located above the pillar garnish as well.
However, in the conventional guide bracket, the dimension of a clearance between the two guide walls was so set as to accommodate the folded airbag with no gaps. With this construction, if an output of the inflator for supplying inflation gas to the airbag is great, the airbag inflates rapidly in between the confronting guide walls, which can cause gas leakage. That is, the airbag must be provided with certain gas-leakage preventing means such as reinforcing patch, in a region of the guide bracket and therearound. This has increased manufacturing processes and volume of the airbag.